Relationship Between Urinary Iodine Concentration and the Prevalence of Thyroid Nodules and Subclinical Hypothyroidism.

The aim of the study was to investigate the iodine intake in the resident population in Xi'an and analyze the relationship between iodine nutritional status and the prevalence of subclinical hypothyroidism and thyroid nodules (TNs). A total of 2507 people were enrolled in Xi'an. Venous serum thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), urinary iodine concentration (UIC), and thyroid ultrasonography were collected. Patients with abnormal TSH were checked for free thyroxine (FT4) and triiodothyronine (FT3). Adults in Xi'an had median UICs of 220.80 µg/L and 178.56 µg/l, respectively. A sum of 16.78% of people had subclinical hypothyroidism. Both iodine excess and iodine deficit increased the frequency of subclinical hypothyroidism. The lowest was around 15.09% in females with urine iodine levels between 200 and 299 µg/l. With a rate of 10.69%, the lowest prevalence range for males was 100-199 µg/l. In Xi'an, 11.37% of people have TNs. In comparison to other UIC categories, TN occurrences were higher in females (18.5%) and males (12%) when UIC were below 100 µg/l. In conclusion, iodine intake was sufficient in the Xi'an area, while the adults' UIC remains slightly higher than the criteria. Iodine excess or deficiency can lead to an increase in the prevalence of subclinical hypothyroidism. Patients with iodine deficiency are more likely to develop TNs.

The application of serum iodine in assessing individual iodine status.

CONTEXT: The prevalence of thyroid disease in China is on the rise, and this could be partly associated with excessive iodine intake in some individuals; therefore, increased attention is being paid to individual iodine status. However, current indices are not appropriate for evaluating individual iodine status. OBJECTIVE: To evaluate the association between serum iodine and urinary iodine (UI), as well as thyroid diseases, and provide an excellent base for future individual iodine status assessment. DESIGN, SUBJECTS AND MEASUREMENTS: A total of 902 adults were enrolled in this study including 325, 286 and 291 subjects from regions in China where iodine is adequate, sufficient and in excess, respectively. Serum iodine, UI and thyroid function were assessed, and ultrasonography performed in all subjects. RESULTS: The median serum iodine values of adults with subclinical hypothyroidism, high serum autoantibody and thyroid nodules were significantly higher than those of euthyroid adults (P<0.05). A serum iodine level higher than 100 µg/L was considered as a risk factor for thyroid diseases. Serum iodine had strong nonlinear correlations with UI and thyroid function. When thyroid function was taken as a gold standard, the area under the receiver operating characteristic (ROC) curve for serum iodine was 0.752 and UI was 0.507 for subjects with lower serum iodine and UI levels. The area for serum iodine was 0.773 and UI was 0.638 for subjects with higher serum iodine and UI levels. The areas under these curves were significantly different (P<0.001). CONCLUSION: In adults, serum iodine had a strong nonlinear correlation with UI and a high level of serum iodine was a risk factor for thyroid diseases.

Synergic actions of polyphenols and cyanogens of peanut seed coat (Arachis hypogaea) on cytological, biochemical and functional changes in thyroid.

In animals, long-term feeding with peanut (Arachis hypogaea) seed coats causes hypertrophy and hyperplasia of the thyroid gland. However, to date there have been no detailed studies. Here, we explored the thyroidal effects of dietary peanut seed coats (PSC) in rats. The PSC has high levels of pro-goitrogenic substances including phenolic and other cyanogenic constituents. The PSC was mixed with a standard diet and fed to rats for 30 and 60 days, respectively. Animals fed with the PSC-supplemented diet showed a significant increase in urinary excretion of thiocyanate and iodine, thyroid enlargement, and hypertrophy and/or hyperplasia of thyroid follicles. In addition, there was inhibition of thyroid peroxidase (TPO) activity, 5'-deiodinase-I (DIO1) activity, and (Na+-K+)-ATPase activity in the experimental groups of rats as compared to controls. Furthermore, the PSC fed animals exhibited decreased serum circulating total T4 and T3 levels, severe in the group treated for longer duration. These data indicate that PSC could be a novel disruptor of thyroid function, due to synergistic actions of phenolic as well as cyanogenic constituents.

Excessive iodine intake, water chemicals and endemic goitre in a Sudanese coastal area.

OBJECTIVE: To study the associations between intakes of iodine and water chemicals and the thyroid gland status of schoolchildren living in the coastal city of Port Sudan. DESIGN: In our previous nationwide study on goitre, it was observed that the prevalence of goitre was high in Port Sudan city despite high urinary iodine excretion. A cross-sectional study including schoolchildren aged 6­12 years was designed. Measurements determined the prevalence of goitre, urinary iodine concentration and thiocyanate secretion in casual urine samples, serum levels of thyroxine, triiodothyronine, thyroid-stimulating hormone and thyroglobulin, as well as the levels of Cl⁻, F⁻, Ca²âº, Mg²âº and total hardness of drinking water. SUBJECTS: Schoolchildren (n 654) aged 6­12 years. SETTING: Port Sudan city is located at the western bank of the Red Sea. The city is surrounded by a mountainous area known as the Red Sea Hills. It is the main sea port in the Sudan, inhabited by ethnically and socio-economically heterogeneous populations. RESULTS: The prevalence of goitre in Port Sudan was 34.86% while the median urinary iodine concentration was 46,4µg/dl. Out of thirty-one pupils from Port Sudan, twenty-four (77.42 %) were found to have urinary iodine concentration greater than 30µg/dl and twelve (38.71 %) had different degrees of biochemical hypothyroidism. Excessive concentrations of Cl⁻, Ca²âº, Mg²âº and water hardness (369.2, 116.48, 60.21 and 539.0mg/l, respectively) were detected in drinking water samples collected from Port Sudan that exceeded levels permitted by the WHO. CONCLUSIONS: The coastal city of Port Sudan is a goitre-endemic area. In contrast to other Sudanese cities in which endemic goitre is related to iodine deficiency, goitre in Port Sudan is associated with iodine excess. Water chemicals seemed to have no effects on thyroid status.

Low urinary iodine postpartum is associated with hypothyroid postpartum thyroid dysfunction and predicts long-term hypothyroidism.

BACKGROUND: Postpartum thyroid dysfunction (PPTD) is characterized by an early hyperthyroid phase followed, with peak prevalence at 6 months, by a hypothyroid phase which carries a risk of long-term hypothyroidism. Iodine has a major effect on thyroid function. Western Australia has previously been shown to be iodine replete. OBJECTIVE: To examine the iodine status of women with and without PPTD and the relationship of iodine status postpartum with long-term hypothyroidism. DESIGN: Case-control with follow-up. PATIENTS: A total of 149 women at 6 months postpartum (74 PPTD, 75 controls) with 98 (46 PPTD, 52 controls) followed up at 12 years. MEASUREMENTS: Urinary iodine concentration (UIC) and thyroid function at 6 months postpartum; thyroid function at 12-year follow-up. RESULTS: At 6 months postpartum, median UIC (quartiles) for observed TSH ranges were: for TSH < 0·4 mU/l 130·0 µg/l (82·0, 170·0); for TSH 0·4-4·0 mU/l 123·0 µg/l (80·5, 168·0); for TSH > 4·0 mU/l 85·0 µg/l (40·0, 141·5), P = 0·018. The odds ratio (OR) of hypothyroid PPTD with each unit of decreasing log iodine was 2·54, (95%CI: 1·47, 4·35), and with UIC < 50 µg/l, OR 4·22, (95%CI: 1·54, 11·55). In the long term, decreased log UIC significantly predicted hypothyroidism at 12-year follow-up (P = 0·002); as did UIC < 100 µg/l (P = 0·03) and UIC < 50 µg/l (P = 0·02). The association was independent of antibody status. CONCLUSION: Low UIC measured at 6 months postpartum is associated with hypothyroid PPTD and independently predicts long-term hypothyroidism. We believe that it results from more severe preceding destructive thyroiditis, with discharge of thyroidal iodine, and thereby predicts a greater risk of long-term hypothyroidism.

Geographical influences on thyroid abnormalities in adult population from iodine-replete regions: a cross-sectional study.

The studies on the increasing incidence of thyroid abnormalities are scarce. The aim of this current study was to ascertain the effects of geographical region on thyroid abnormalities under the context of universal salt iodization (USI). We randomly selected 1255 participants residing in inland and 1248 in coast, with the determination of urinary iodine concentration (UIC) and functional and morphological abnormalities of thyroid gland. The median UIC was significantly higher for the inland participants (188.5 µg/L) than the coastal participants (128.5 µg/L; p < 0.001), indicating iodine sufficiency in both populations according to the recommended assessment criteria by the World Health Organization. However, the spectrum of thyroid abnormalities varied between regions, with hypothyroidism prevalent in inland and thyroid nodules in coast. The associations between region and thyroid abnormalities via binary logistic regression models showed that the coastal participants were at a higher risk of total thyroid abnormalities than those from the inland (OR 1.216, 95% CI 1.020-1.449), after the adjustment of ten confounders (demographical characteristics, smoking status, metabolism syndrome, and hyperuricemia). These results indicated that further investigations of the adverse effects of hypothyroidism and thyroid nodules on health burden is urgently needed to sustain USI program.

Thyroid Autoimmunity and Dysfunction in Sri Lankan Children and Adolescents After 22 Years of Sustained Universal Salt Iodization.

Background: Sri Lanka introduced universal salt iodization (USI) in 1995 after which we demonstrated a high thyroglobulin antibody (TgAb) prevalence in 1998. However, it is unclear whether thyroid autoimmunity persists in the long term in populations exposed to sustained USI and whether such populations have an excess of thyroid dysfunction. We evaluated the prevalence of thyroid autoantibodies and dysfunction in Sri Lankan children and adolescents after more than two decades of sustained USI. Methods: We selected 10- to 18-year-old subjects of both sexes (randomized cluster sampling) from all 9 provinces of Sri Lanka in this cross-sectional study. Blood, urine, and anthropometric data were collected and thyroid ultrasound scans were performed. Validated statistical methods were used to derive local population-specific reference ranges for all thyroid parameters. We also measured urine iodine concentration (UIC), salt, and water iodine concentrations. Results: Blood and urine samples from 2507 and 2473 subjects respectively, and ultrasound scans from 882 subjects were analyzed. Population-derived upper limits for thyroid peroxidase antibody (TPOAb) and TgAb, and reference ranges for triiodothyronine, thyroxine, and thyrotropin (total and age-year-related groups) were significantly different from manufacturer's reference ranges. Using these derived ranges, the prevalence of TPOAb was 10.3% and TgAb was 6.4%. Of the TPOAb-positive subjects, TPOAb were of low concentration in 66.2% (1-3 times the upper limit of the reference range [ULRR]) and showed the strongest association with subclinical hypothyroidism (SCH) at the highest concentrations (>4 ULRR). The prevalence of SCH was 3%. Median UIC (interquartile range) was 138.5 µg/L (79.4-219.0) with regional variability, and median thyroglobulin was 8.3 ng/mL (4.1-13.5). Goiter prevalence was 0.6% and 1.93% (thyroid volume compared to age and body surface area, respectively). Salt and water iodine concentrations were satisfactory. Conclusions: Sri Lanka has safely and effectively implemented USI with good sources of iodine, leading to sustained iodine sufficiency over more than two decades. The early postiodization TgAb surge (42.1%) has settled (6.4%), and despite a persistently high TPOAb prevalence (10.3%), SCH prevalence remains low (3%). Further studies should be undertaken to monitor thyroid autoimmune dysfunction in Sri Lankan children, using age-specific, population-derived reference ranges.

Relationship between Thyroid Status during the First Trimester of Pregnancy and Neonatal Well-Being.

Iodine is an essential micronutrient for the synthesis of thyroid hormones. The proper functioning of the thyroid axis is essential for the normal development of the nervous system, especially in the first trimester of gestation. The aim of the present study was to analyze the perinatal outcomes, anthropometry, and APGAR test scores of newborns and to relate them to maternal thyroid status. A total of 190 newborns participated in the study. No correlation was found between thyroid stimulating hormone (TSH) and maternal ioduria values in the first trimester of gestation with the weight or length of the newborn, or the APGAR score at one minute after birth. However, we found significant differences between the APGAR scores of children whose mothers had an iodine sufficiency level in the first trimester compared to the children of mothers with iodine deficiency. Similarly, the APGAR scores of children whose mothers had a TSH > 4 have significantly better APGAR scores than the children of mothers with a TSH < 4. Likewise, we found significant differences between the measurements of the newborns depending on whether their mothers smoked. The children of mothers who took iodine supplements or iodized salt obtained the highest APGAR score at one and five minutes after birth. It is essential to focus on recommending adequate consumption of iodine supplements and iodized salt prior to gestation and at least during the first trimester to achieve better fetal well-being.

Urinary Iodine and Genetic Predisposition to Hashimoto's Thyroiditis in a Chinese Han Population: A Case-Control Study.

Background: We aimed to examine the association of urinary iodine concentration with Hashimoto's thyroiditis (HT) risk, and particularly, to investigate whether the HT-related genetic variations might modify the effects of urinary iodine on HT in the Chinese Han population. Methods: We conducted a case-control study with 1723 Chinese (731 cases, 992 controls). The associations between urinary iodine concentration and HT risk were analyzed using logistic regression models. The effects of interactions between the genetic risk scores (GRSs) and urinary iodine on HT risk were assessed by including the respective interaction terms in the models. We also applied restricted cubic spline regression to estimate the possible nonlinear relationship. The multinomial logistic regression models were performed to determine the associations of urinary iodine with euthyroid-HT and hypothyroidism-HT. Results: After controlling for potential confounders, the odds of HT increased with increasing quartiles of urinary iodine concentration: adjusted odds ratios (ORs) and 95% confidence intervals [CIs] were 1.45 [1.06-1.99], 1.66 [1.17-2.34], and 2.07 [1.38-3.10] for the quartiles 2, 3, and 4, respectively, compared with the first quartile (p for trend <0.001). Multivariable restricted cubic spline regression analysis further demonstrated that there was a near-linear association between urinary iodine concentration and HT risk (p-overall <0.001; p-nonlinear = 0.074). However, we did not find significant interactions between urinary iodine and GRSs on the risk of HT (all p for interaction >0.05). Interestingly, we found that each increment of urinary iodine was associated with a more than twofold increase in the odds of hypothyroidism-HT (adjusted OR = 2.64 [CI = 1.73-4.05]), but not with euthyroid-HT (p > 0.05). Conclusions: Higher urinary iodine concentration was associated with increased risk of HT, and this association was near linear, indicating that increased urinary iodine has a continuous and graded impact on HT risk. Moreover, the iodine-HT association was not modified by genetic predisposition to HT. Interestingly, urinary iodine concentration was significantly associated with increased risk of hypothyroidism.

The relationship between thyroid dysfunction and nephrotic syndrome: a clinicopathological study.

Abnormalities of thyroid function are common in patients with nephrotic syndrome (NS). However, a limited number of studies have reported on the association between clinicopathologic features and thyroid dysfunction in patients with NS. We retrospectively studied 317 patients who had been definitively diagnosed with NS. The NS patients with thyroid dysfunction showed higher urine protein, creatinine and lipid levels and lower albumin and hemoglobin than those with normal thyroid function, with no significant differences of pathological types. After dividing thyroid dysfunction groups into five subgroups, interestingly, membranous nephropathy was the most common pathologic type, both in normal thyroid group and in subclinical hypothyroidism group (40.4% and 46.7%, respectively), followed by minimal change disease (28.1% and 21.7%, respectively); while in the hypothyroid, low T3, and low T3T4 groups minimal change disease is now the leading type (48.8%, 33.3% and 38.6%, respectively). High levels of urinary protein, creatinine, cholesterol, and platelets were independent risk factors predicting thyroid dysfunction, while higher albumin and hemoglobin were protective factors. We demonstrated that the type of renal pathology was different among NS patients in different thyroid dysfunction subgroups. Interpretation of the interactions between thyroid and renal function is a challenge for clinicians involved in the treatment of patients with NS.

Excess urinary iodine is associated with autoimmune subclinical hypothyroidism among Egyptian women.

Excessive iodine exposure was reported to be associated with thyroid dysfunctions. The aim of this study is to evaluate the link between excess urinary iodine as the prime indicator of excessive iodine intake and autoimmune subclinical hypothyroidism (SCH) among Egyptian women. Seventy three women with autoimmune SCH and 60 age- matched healthy women as controls were enrolled in this study. TSH, FT4, urinary iodine concentrations (UIC) and thyroid peroxidase antibody (TPOAb) were estimated. The levels of urinary iodine were significantly higher in patients with SCH as compared with control subjects, (326.97 112.98 vs. 274.45 98.75 microg/l, p<0.01). In patients with SCH, there was a significant correlation between UIC and TSH levels. Also, a significant correlation between UIC and TPOAb was found. We conclude that excessive iodine intake may trigger thyroid autoimmunity and eventually thyroid hypofunction among Egyptian women.

Hypothyroidism and Iodine Deficiency in Children on Chronic Parenteral Nutrition.

BACKGROUND AND OBJECTIVES: Iodine is an essential trace element for maintenance of normal thyroid function. Normal thyroid function is a prerequisite for neurocognitive development and growth in children. In the United States, iodine is not routinely added as a trace element in parenteral nutrition (PN). Our objective was to determine the prevalence of iodine deficiency and hypothyroidism in children on chronic PN. METHODS: This was a cross-sectional study of children <17 years of age and using PN for >6 months at a tertiary children's hospital. Primary outcomes were spot urine iodine concentration (UIC), serum thyrotropin, and free thyroxine levels. RESULTS: Twenty-seven patients were identified (74% male). The median age at screening was 48 months (range: 7-213 months). The median duration on PN was 27 months (range: 11-77 months). Seventeen out of 20 patients (85%) were iodine deficient (spot UIC <100 µg/L), whereas 11 out of 20 patients (55%) were severely iodine deficient (spot UIC <20 µg/L). The prevalence of acquired hypothyroidism (elevated thyrotropin, low free thyroxine, and UIC <100 µg/L) was 33% (n = 8). None of the children with hypothyroidism screened for autoimmune thyroiditis had positive test results. There was no statistically significant association between duration of PN use and development of iodine deficiency (P = .08) or hypothyroidism (P = .96). CONCLUSIONS: Children on chronic PN are at risk for developing iodine deficiency and resultant hypothyroidism; hence, these children should be screened for these outcomes. Further studies are needed to define the temporal onset of iodine deficiency and timing to thyroid dysfunction related to PN.

The effect of L-thyroxine substitution on oxidative stress in early-stage diabetic nephropathy patients with subclinical hypothyroidism: a randomized double-blind and placebo-controlled study.

PURPOSE: To study oxidative stress status of early type 2 diabetic nephropathy (DN) patients with subclinical hypothyroidism (SCH) and to assess effect of L-thyroxine therapy on the oxidative stress in these patients. METHODS: It is a randomized double-blind and placebo-controlled trial. A total of 48 patients with early type 2 DN were included as Euthyroid group, and 92 early type 2 DN with SCH were selected and randomly assigned to L-thyroxine treatment group (LT4 group) and placebo group (SCH group). Changes in urinary albumin excretion rate (UAER), serum malondialdehyde (MDA), superoxide dismutase (SOD) activity, urine 8-hydroxyl deoxyguanosine (8-OHdG), serum creatinine, estimated glomerular filtration rate, and lipid profile before and after 24 weeks of follow-up were examined and compared. RESULTS: The levels of UAER, MDA, 8-OHdG were higher, while the SOD activity was lower in DN patients with SCH than in DN patients (p < 0.05 for all). In the LT4 group, the levels of UAER, MDA, 8-OHdG decreased significantly (p < 0.05) to levels no longer different from the Euthyroid group. The SOD activity increased significantly. But in SCH group, the levels of mAlb, MDA, 8-OHdG were greater after 24 weeks of follow-up and greater than patients in the Euthyroid group. SOD activity decreased significantly after 24 weeks in the SCH group (p < 0.05). CONCLUSION: Oxidative stress is greater in the DN patients with SCH, and SCH may exacerbate kidney injury in early DN patients. The LT4 treatment may decrease the oxidative stress and attenuate renal injury in DN patient with SCH.

[Determining the thyroid hormones T3 and T4 in the urine: an unreliable test for hypothyroidism]. / Bepaling van schildklierhormoon (T3 en T4) in de urine: een weinig betrouwbare test voor de diagnose 'hypothyreoïdie'.

A 24-year-old woman complained of tiredness, sensitivity to cold, and feelings of depression. A diagnosis of hypothyroidism based on decreased 24 h urinary T3 and T4 excretion was made, and she was treated with levothyroxin. No blood tests were done. She was referred with the question if she had other endocrine disorders. Her periods were regular, and on physical examination no abnormalities except slight acne were found. Similarly, hypothyroidism was diagnosed by decreased thyroid hormone excretion in 24 h urine, again without blood tests, in a 68-year-old woman whose mother had a goitre, and who had already been prescribed liothyronine. She had no complaints, and physical examination was unremarkable. The thyroid gland was not palpable. Thyroid peroxidase antibodies were absent in both patients. After discontinuation of medication with thyroid hormones they both remained euthyroid. It is concluded that thyroid disease did not exist in those 2 patients. Measurement of 24 h urinary T3 and T4 excretion is not an accurate diagnostic test for hypothyroidism.

Iodine is associated to semen quality in men who undergo consultations for infertility.

The role that adequate iodine intake could have on the male reproductive function is not entirely known. The aim of this study is to determine whether there is a relation between male infertility and urinary and semen iodine levels in 96 couples who underwent consultation for infertility. The median of semen iodine was higher in men who consumed iodized salt than in those who consumed non-iodized salt (p=0.019). Men with a higher semen iodine level had more morphological alterations in spermatozoa (p=0.032). Men with a higher urinary iodine level had a lower motile sperm count according to the "direct swim-up" technique (p=0.044). Men >3years without successfully achieving pregnancy had a higher urinary iodine level than those with ≤ 3years (p=0.035). In conclusion, iodine may play a role in the quality of semen: an increase in semen iodine levels is associated with different variables related to male infertility.

Definition of reference ranges for free T4, TSH, and thyroglobulin levels in healthy subjects of the Jaén Health District. / Definición de los rangos de referencia de T4 libre, TSH y tiroglobulina en sujetos sanos del Distrito Sanitario de Jaén.

BACKGROUND AND OBJECTIVES: The treatment guidelines for thyroid dysfunction recommend defining reference ranges for thyroid hormones in each area through assessment of local population data considering the iodine nutritional status. The aim of this study was to define the reference ranges of free thyroxine (FT4), TSH, and thyroglobulin levels in a general population from Jaen, an area of southern Spain with an adequate iodine nutritional status, and whether they were associated with urinary iodine levels. PATIENTS AND METHODS: A cross-sectional study was conducted in 1,003 subjects of the general population of the Jaen Health District. Levels of urinary iodine, FT4, TSH, thyroglobulin, and thyroid peroxidase (TPO) antibodies were measured according to age and sex. RESULTS: Median and mean urinary iodine levels were 110.59µg/L and 130.11µg/L respectively. Median TSH level was 1.83µIU/mL (p2.5=0.56µIU/mL, p97.5=4.66µIU/mL). Median FT4 level was 0.84ng/dL (p2.5=0.62ng/dL, p97.5=1.18ng/dL). TPO antibodies were detected in 5.7% of subjects. There was no correlation between urinary iodine levels and FT4, TSH or TPO antibodies. Subjects with positive TPO antibodies had higher TSH levels (3.34µIU/L versus 2.14µIU/mL, P=.001; odds ratio=2.42). CONCLUSIONS: Urinary iodine levels in Jaen are optimal according to World Health Organization standards. Reference ranges of FT4, TSH, and thyroglobulin do not differ from those reported in the literature and are no associated to urinary iodine levels. The prevalence of positive TPO antibodies was similar to that reported in other Spanish areas.

Role of Microalbuminuria in Predicting Cardiovascular Mortality in Individuals With Subclinical Hypothyroidism.

PURPOSE: Studies suggest that subclinical hypothyroidism (SCH) is related to cardiovascular mortality (CVM). We explored the role of microalbuminuria (MIA) as a predictor of long-term CVM in population with and without SCH with normal kidney function. MATERIALS AND METHODS: We examined the National Health and Nutrition Education Survey - III database (n = 6,812). Individuals younger than 40 years, thyroid-stimulating hormone levels ≥20 and ≤0.35mIU/L, estimated glomerular filtration rate <60mL/minute/1.73m2 and urine albumin-to-creatinine ratio of >250mg/g in men and >355mg/g in women were excluded. SCH was defined as thyroid-stimulating hormone levels between 5 and 19.99mIU/L and serum T4 levels between 5 and 12µg/dL. MIA was defined as urine albumin-to-creatinine ratio of 17-250mg/g in men and 25-355mg/g in women. Patients were categorized into the following 4 groups: (1) no SCH or MIA, (2) MIA, but no SCH, (3) SCH, but no MIA and (4) both SCH and MIA. RESULTS: Prevalence of MIA in the subclinical hypothyroid cohort was 21% compared to 16.4% in those without SCH (P = 0.03). SCH was a significant independent predictor of MIA (n = 6,812), after adjusting for traditional risk factors (unadjusted odds ratio = 1.75; 95% CI: 1.24-2.48; P = 0.002 and adjusted odds ratio = 1.83; 95% CI: 1.2-2.79; P = 0.006). MIA was a significant independent predictor of long-term all-cause (adjusted hazard ratio = 1.7, 95% CI: 1.24-2.33) and CVM (adjusted hazard ratio = 1.72, 95% CI: 1.07-2.76) in subclinical hypothyroid individuals. CONCLUSIONS: In a cohort of subclinical hypothyroid individuals, the presence of MIA predicts increased risk of CVM as compared to nonmicroalbuminurics with SCH. Further randomized trials are needed to assess the benefits of treating microalbuminuric subclinical hypothyroid individuals and impact on CVM.

Iodine excretion with urine and thyrotrophic hormone concentration in normal and complicated pregnancies in the industrial region of iodine deficiency.

A sufficient amount of iodine in food is necessary for the thyroid gland to produce hormones during pregnancy. The aim of our work was to evaluate iodine and thyrotrophic hormone (TSH) concentration in urine, free triiodothyronine (fT3) and thyroxine (fT4) in complicated pregnancies in Upper Silesia (region of iodine deficiency in Poland) in comparison with normal pregnancies. In both groups the iodine content in urine was evaluated by a quick test and serous concentrations of TSH, fT3 and fT4 were determined by a radioimmunological method. We found the iodine excretion with urine below 100 microg/L in 29.15% of all women under study, i.e. an insufficient supply of this element. The reduced iodine concentration in urine was found to be more often in women with imminent premature delivery. Moreover, it was found that in II trimester the concentration of iodine excreted with urine had been significantly lower comparing to the patients examined in III trimester. We found significantly higher concentration of thyrotrophic hormone in pregnant women with iodine excretion below 100 microg/L of urine. Evaluation of the iodine concentration in urine may be a simple screening test to determine the supply of this element in a diet. Moreover, our studies demonstrate the necessity for the iodine supplementation in pregnant women in the Silesian region--an area of iodine deficiency in Central Europe.

The Urine Iodine to Creatinine as an Optimal Index of Iodine During Pregnancy in an Iodine Adequate Area in China.

CONTEXT: Iodine nutrition is a global event, especially for pregnant women. OBJECTIVE: To develop applicable index of iodine intake for population during pregnancy. DESIGN, SETTING, AND PARTICIPANTS: From 2012 to 2014, pregnant women at less than 8 weeks of gestation (n = 222) and reproductive-age women (n = 827) participated in this study. The pregnant women were evaluated at follow-up visits at 8, 12, 16, 20, 28, and 36 weeks of gestation and 3 and 6 months postpartum. MAIN OUTCOME MEASURES: Twenty-four-hour urine samples were collected at weeks 8 of gestation. Urine iodine (UI) and creatinine (Cr) and serum thyroglobulin were measured in all of the subjects. Circulatory iodine was measured using inductively coupled plasma-mass spectrometry at 8, 20, and 36 weeks of gestation and 6 months postpartum. RESULTS: The median UI concentration decreased from 183.6 to 104.2 µg/L during pregnancy. The serum iodine (SI) changes were similar to the UI to creatinine ratio (UI/Cr). The SI level was lowest at the eighth week of gestation (60.5 µg/L), which rose significantly until 20 weeks (106.5 µg/L) and then began to decline (36 wk, 84.7 µg/L). The 24-hour UI excretion measurement was regarded as the gold standard. The area under the receiver-operating characteristic curve for UI/Cr was 0.92 for iodine deficiency diagnoses and 0.78 for SI. The area for SI was 0.82 for excessive iodine diagnoses and 0.75 for UI/Cr. The areas under these curves were significantly different (P < .001). The areas under the receiver-operating characteristic curve for UI were 0.61 (P = .11) and 0.65 (P = .08) for iodine deficiency and excessive iodine diagnoses, respectively. Additionally, for thyroglobulin, these values were 0.54 (P = .53) and 0.53 (P = .74), respectively. CONCLUSIONS: Iodine intake, as assessed by spot UI concentration in pregnant women, is inaccurate and increases the prevalence of iodine deficiency. The UI/Cr better reflects the 24-hour iodine excretion and circulating iodine levels during pregnancy and the postpartum period.

Borderline-low serum thyrotropin level is correlated with increased fasting urinary hydroxyproline excretion.

BACKGROUND: Recent studies suggest that even mildly supraphysiologic thyroid hormonal status accelerates bone loss. In hyperthyroidism, increased bone resorption is the predominant mechanism for bone loss. We postulated that the changes in thyroid hormone status as reflected by low-normal and minimally subnormal serum thyrotropin level would have an effect on bone turnover and could be detected by a simple, noninvasive marker of bone resorption, fasting urinary total hydroxyproline-creatinine excretion (THP/Cr). METHODS: We retrospectively identified ambulatory patients with a restricted range of diagnoses who had had measurements of thyrotropin and THP/Cr performed within +/- 21 days. RESULTS: Of the 86 patients, 47 had thyrotropin levels greater than 1.0 mU/L. In these patients, no correlation was evident for thyrotropin and THP/Cr. Of the other 39 patients, 11 had suppressed thyrotropin levels (less than 0.1 mU/L) and showed clearly elevated values for THP/Cr, as expected from previous studies of hyperthyroidism. For 28 patients with thyrotropin in the borderline and low-normal range of 0.1 to 1.0 mU/L, a significant negative correlation with THP/Cr was found. The THP/Cr was positively correlated with serum alkaline phosphatase level, as expected with increased bone turnover. CONCLUSIONS: These results add further support to the hypothesis that even a minimal excess of thyroid hormones increases bone turnover and may contribute to accelerated bone loss.